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Abrasives

Grinding Wheel Geometry 361

Grinding Wheel Geometry provides an overview of common grinding wheel geometries according to American National Standards Institute (ANSI) standards. ANSI standards provide a common language for grinding wheels, including letter designations for each part of the wheel, as well as guidelines for wheel design and usage. Most grinding wheels are one of eight basic types that are variations of straight and cup wheels. The variations come from different wheel features, such as reliefs and recesses, which make them suitable for grinding different part shapes.

Selecting and using the best grinding wheel for an operation requires an understanding of wheel geometry. After taking this class, users should be able to describe common wheel geometries and the applications appropriate for each.

Difficulty Advanced
Format Online
Number of Lessons 17
Language English

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The Importance of Wheel Geometry
Major Wheel Categories
Wheel Features
Wheel Dimensions
Wheel Features and Dimensions Review
ANSI Standard
Letter Designations
Numbered Wheel Types
Wheel Dimension Review
Straight Wheels
Cylinder Wheels
Wheel Types 5 and 7
Wheel Types 6, 11, and 12
Saucer Wheels
Grinding Wheel Review
Wheel Profiles
Wheel Geometry Review

Explain the factors that determine wheel selection.
Describe the basic anatomy of a grinding wheel.
Describe the purpose of different wheel features.
Identify common dimensions for grinding wheels.
Describe the purpose of ANSI grinding wheel standards.
Describe ANSI letter designations for grinding wheel dimensions.
Describe the ANSI standard for numbering grinding wheel types.
Describe the key features of a Type 1 straight wheel.
Describe the key features of a Type 2 cylinder wheel.
Describe the key features of a Type 5 recessed one-side wheel. Describe the key features of a Type 7 double-recessed wheel.
Describe the key features of a Type 6 straight cup wheel. Describe the key features of a Type 11 flaring cup wheel. Describe the key features of a Type 12 dish wheel.
Describe the key features of a Type 13 saucer wheel.
Describe wheel profiles.

Vocabulary Term

Definition

abrasive grain

A hard, sharp particle of material used to make abrasive tools such as grinding wheels. Abrasive grains abrade or rub and plow away material to create precise and smooth surfaces.

adhesive

A substance used to join two or more materials. Adhesives include glues and epoxies.

American National Standards Institute

ANSI. A private, nonprofit organization that administers and coordinates voluntary standards and systems. The American National Standards Institute standardizes tool nomenclature.

ANSI

American National Standards Institute. A private, nonprofit organization that administers and coordinates voluntary standards and systems. ANSI standardizes tool nomenclature and carbide insert classifications.

base plate

A precisely ground workholding device upon which grinding wheels are mounted using screws. The base plate is also called a tool body or subplate.

bond

The material that holds abrasive grains together in a grinding wheel. Bond, or bonding material, can be vitrified, resin, rubber, or metal.

bore

The hole diameter of a grinding wheel. The bore of a wheel indicates the size flange needed to mount it.

centerless grinding

A type of cylindrical grinding in which a cylindrical part is supported on a work rest blade and guided between a grinding wheel and a regulating wheel. Centerless grinding requires that both the workpiece and the grinding wheel rotate.

center-type cylindrical grinding

A grinding process that holds a cylindrical part on each end during the grinding process. Center-type cylindrical grinding rotates both the part and the grinding wheel.

chip

A small piece of material that is removed from a workpiece. Chips are formed when a tool cuts or grinds a material.

clamps

A workholding device that holds objects together by applying inward pressure. Clamps may have two jaws or one fixed and one moving component.

clearance

An intentional amount of space left between two components. Clearance is often required to prevent undesirable contact between a grinding wheel and a workpiece.

contour grinding

A grinding operation that uses the grinding wheel to incrementally move in the cross feed direction and form a shape in the workpiece that does not resemble that of the grinding wheel periphery. Contour grinding forms the shape of the workpiece by the combined motion of the table and the cross feed.

creep feed grinding

A type of surface grinding in which the depth of cut is increased while the feed rate is decreased. Creep feed grinding is used for large amounts of material removal.

cross section

A section of a feature that is formed by an intersecting imaginary plane. Cross sections show the geometry of grinding wheels.

cup wheels

An abrasive tool that is shaped like a bowl or cup with a grinding surface along its rim. A cup wheel has sides that are either straight, known as Type 6, or flaring, known as Type 11.

cutoff operations

The use of a thin grinding wheel to cut through material and separate it into two pieces. Cutoff operations can be performed with straight wheels, depending on their thickness.

cylinder wheels

An abrasive tool that has a ring shape with a grinding surface along its rim. Cylinder wheels are designated by American National Standards Institute as Type 2 wheels.

cylindrical grinding

A common grinding process that holds a cylindrical part on each end or uses a chuck or collet to hold the part during grinding. Cylindrical grinding rotates both the part and grinding wheel.

depth

The horizontal measurement of recesses and reliefs. The hole on a plate-mounted wheel also have depth dimensions.

diameter

The distance from one edge of a circle to the opposite edge that passes through its center. Diameter measures a circular object at its widest point.

dimensions

The various measurements of a tool or part. The basic dimensions of a grinding wheel include the diameter, width or thickness, and the bore size.

dish wheels

An abrasive tool that has a concave shape, much like a dish or dinner plate. Dish wheels are ANSI Type 12, and their shape prevents the entire wheel from contacting a workpiece.

dress

To remove swarf, dull grains, and bonding material from a grinding wheel by fracturing away the wheel surface. Dressing the wheel also sharpens the wheel.

face

The part of a grinding wheel with the greatest surface area. The face of a regular straight or cup wheel is the side of the wheel, but the face of a centerless grinding wheel is its periphery.

face plate

A metal plate with uniform holes that is used to mount a grinding wheel to a spindle. The face plate holes accommodate studs that can then be used to fix the grinding wheel in place with nuts.

fixtures

A customized workholding device used to position and hold a grinding wheel or workpiece. Fixtures are built to hold a specific design.

flange

A flat or raised metal disk that clamps the wheel on its side. The flanges protect the center of the wheel from damage, and they position the wheel and hold it on the machine spindle.

flat

The bottom of a recess or the horizontal area that lies between the relief edge and the wheel edge. Flats occur in grinding wheels with recesses and/or reliefs.

geometry

The collective angles formed by the unique dimensions of a cutting tool. The geometry of a grinding wheel depends on the geometry of the workpiece.

grinding wheel

A wheel made of abrasive grains that are held together by a bonding material. A grinding wheel rotates and grinds away microscopic chips of material and can produce very fine surface finishes.

horizontal spindle surface grinding

A grinding process that wears away precise amounts of a flat workpiece using a spindle that is parallel to the floor. Horizontal spindle surface grinding is the most common form of surface grinding.

milling cutters

A multipoint cutting tool that has teeth around its cutting surface. Milling cutters are used on milling machines.

mounting plate

A metal plate that is affixed to a grinding wheel using adhesive or clamps. A mounting plate attaches the wheel to the spindle.

nut-inserted disc

A type of grinding wheel that has nuts embedded into one edge. Nut-inserted discs can be used to mount cylinder wheels.

nuts

A metal component with a usually hexagonal outer diameter that has a threaded hole at its center. Nuts are used in combination with a threaded shaft to fix or clamp a component, part, or grinding wheel in place.

Occupational Safety and Health Administration

OSHA. A government agency under the U.S. Dept. of Labor that sets the standards for working conditions in the United States. The Occupational Safety and Health Administration ensures that employees work in safe and healthy environments.

periphery

The outer circular edge or rim of a grinding wheel. Almost all types of grinding wheels grind with their periphery.

profiles

A specialized edge that is added to the face of a wheel to help it conform to a particular grinding operation or part shape. Profiles carry letter designations from A through P in the ANSI standard.

radius

The distance between a point on a circle and its center. The radius of a grinding wheel equals half of its diameter from the center to one edge.

raised flange

A raised metal disk that clamps the wheel and helps center it on the machine spindle. Raised flanges are often used to mount a grinding wheel to a spindle.

recesses

An indentation or a hollow area. Recesses are made on one or both sides of a wheel.

relief

A gradual, angular impression. A relief allows clearance to avoid any side-wall grinding.

saucer wheels

An abrasive tool that is shaped like a dish or dinner plate and has a rounded periphery. A saucer wheel’s grinding surface is the radius of its rounded periphery.

snagging

A form of rough grinding used to remove excess material without regard to surface finish. Snagging wheels should not have a hole diameter larger than one-quarter the measurement of the wheel diameter.

spindle

A precise and motorized rotating component of a machine tool. Typically, grinding and regulating wheels are mounted on a spindle.

straight wheels

An abrasive tool that looks like a flat disk with a grinding surface along its outside edge. Straight wheels are used in grinding and cutoff operations.

studs

An externally threaded fastener that is often threaded at both ends and can be used with a nut. Studs do not have a head and are used to mount cylinder wheels.

surface finish

The smoothness of a part surface after it has gone through all grinding operations. Surface finish is the complete, desired surface.

surface grinders

A common grinding machine that uses a rotating grinding wheel to wear away precise amounts of a flat workpiece surface. Surface grinders can have vertical or horizontal machine spindles.

surface grinders

A machine tool that grinds mainly flat surfaces using a spindle in either a vertical or horizontal configuration. Surface grinders with spindles in the horizontal configuration can grind parts with complex forms using a formed grinding wheel or contour grind using a combination of the axes of movement of the machine.

thickness

The top-to-bottom measurement of a wheel or hole. Thickness is often abbreviated in grinding wheel cross sections with the capital letter T.

tool grinding

A specialized type of grinding performed to sharpen or manufacture cutting tools. Tool grinding often requires precision.

Type 1

The ANSI designation for a straight wheel. A Type 1 wheel looks like a flat disk and has a grinding surface along its outside edge.

Type 11

The ANSI designation for a flaring cup wheel. Type 11 wheels have tapered sides that extend outward at an angle and are often used for tool grinding.

Type 12

The ANSI designation for a dish wheel. Type 12 wheels can grind on either the top flat area of their rims or their periphery and are often used for tool grinding.

Type 13

The ANSI designation for a saucer wheel. Type 13 wheels have the same dimensions as dish wheels but have a rounded periphery.

Type 2

The ANSI designation for a cylinder wheel. A Type 2 wheel has a ring shape with a grinding surface along its rim.

Type 5

The ANSI designation for a straight wheel that is recessed on one side. Type 5 wheels are used for centerless grinding, center-type cylindrical grinding, creep feed grinding, and saw sharpening.

Type 6

The ANSI designation for a cup wheel with straight sides. Type 6 wheels are used for snagging, vertical spindle surface grinding, and tool grinding.

Type 7

The ANSI designation for a straight wheel with a recess on both sides. Type 7 wheels are used for centerless, creep feed, and horizontal grinding and center-type cylindrical grinding.

vertical machine spindles

Oriented in an up-and-down direction, or perpendicular to the floor. Vertical machine spindles are less common than horizontal machine spindles in surface grinding.

vertical spindle surface grinders

A machine that uses a rotating grinding wheel to abrade away precise amounts of a flat workpiece whose spindle is perpendicular to the floor. Vertical spindle surface grinders are less common than horizontal spindle surface grinders.

width

The measurement or size of the grinding edge. Width is often abbreviated in grinding wheel cross sections with the capital letter W.

workpiece

A part that is in the process of being manufactured. A workpiece may be a complete product by itself or one component of a product consisting of many parts.